Danielamartindm,
I saw that you have a
catamaran there, and it may be lacking in
backing plates for its
cleats. If so, deal with that, too.
What you want is line that is strong enough to hold your
boat safely, through the upcoming
hurricane season, with chafing
gear wherever line goes around a cleat. It does mean you have to carry a lot of line, because you will want to double them if you leave the
boat for a named storm. We left our boat (12 tonnes, mono, not prepared for a cyclone) in a windy area for 7 months one time, and one of the
dock lines, which did not have chafe protection, had chafed through 2 of its 3 strands on our return; and our friend who watched the boat for us had had to put a doubler on one of the stern lines, which he saw with only one strand chafed through. Those were 16 mm diameter, 3 strand nylon, and we had not doubled them. If your boat is going to be in a marina, you may be able to get permission to install a couple more dock cleats at your expense, so that you have more attachment points for your lines.
However you decide to do this (I can imagine using
dyneema tails for the dock portion), having put an eye splice with an s/s thimble onto the nylon. Or, you could use stretchy line and
dyneema soft shackle then to the cleats, get more lines on a cleat that way.... You will need to have stretchy line, or introduce something else in the tie up system for yield, because an un-stretchy line like dyneema will jerk the cleats out of your
hull, or out of the dock.
Your boat might need heavier line than we use, because the windage will be more of a factor.
It wasn't part of the question, but consider larger fenders, too, and more of them. People's boats tend to pop the smaller ones in storms.
The cleat hitches themselves had no problems, tied with one full round turn, and two half hitches.
Ann